1064 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Marginal plates are conspicuous, with a gently convex surface. Upper and lower series are not j 
precisely opposite on arms; sometimes alternate. Superomarginals, 22 in number from median inter- 
radial line to extremity of ray, do not encroach much upon abactinal area, but form a rounded bevel. j 
They are nearly quadrate in the interbrachial arc, but are longer than high on proximal two-thirds of 
ray, gradually becoming higher than broad toward the tip. The edge of the plate toward the abactinal 
area is curved. On one interradius there is a small, odd interradial plate, wedged between first supero- ! 
marginals at their upper ends, apparently quite abnormal. General surface of plates is covered with 
rather large, flat, round, hexagonal, or irregular granules which increase in size from center toward 
periphery. Although low, their general surface is very slightly convex, and is smooth. In inter- 1} 
brachial arc the granules of the peripheral series are conspicuously smaller than the others, but on the ! 
ray they may be large, owing to the fusion of granules of the first and second series, which thus form 
long granules, extending from the periphery toward the center. Often long and short granules alter- 1 
nate. Terminal plate is prominent, subspherical, prolonged on the inner and abactinal side, covered 
with scattered granules. 
Inferomarginal plates are equal in number to superomarginals, and encroach rather more upon ]. 
actinal area than do the superomarginals upon abactinal. The 4 median plates of interbrachial arc ’ 
are the largest, with a curved margin toward actinal area. Covering of plates very similar to that of 
superomarginals. In one interradius there is a pedicellaria at outer and upper corner of the second • 
inferomarginal. No others are present on either series of marginals. 
Adambulacral plates are massive, nearly quadrate, with a variable and irregular armature. Furrow 
margin is nearly straight, but abruptly curved at either end of the plate. Armature as follows: (1) A J 
variable number of furrow spines — usually 2 or 3 — short, stubby, very robust, and flattened (in hori- 
zontal plane) with truncate or irregular tips. Middle spine is sometimes much shorter than the 2 
laterals, even becoming reduced to an enlarged granule. Less commonly there are 4 spines, subequal j 
or one much smaller. (2) First adambulacral plate has a giant pedicellaria (similar to those of abacti- 
nal surface) on the actinal surface but flush with the furrow margin, extending the whole length of 
plate and entirely superseding the furrow spines. Four out of the 10 second adambulacrals possess it 
also, but in this case a few additional furrow granules or irregular tubercles also are present. These 
pedicellarise are also present on numerous other adambulacrals, but are not so large, and in all cases 
where present the furrow armature is in consequence reduced in size, usually to flattened upright 
granules or irregular spinules. Pedicellarise occasionally are set obliquely on plate. Rest of actinal 
surface is covered with about 8 to 12 large irregular quadrate and polygonal granules of different sizes, j 
and arranged without constant order. When a suggestion of 2 irregular longitudinal series can be 
seen, the inner has much larger granules. An enlarged granule with a swollen end is usually present 
just aborad to the end of the pedicellaria. 
Mouth plates slightly convex actinally, the united pair rather narrow, 
but rounded furrow margin. Armature stout, composed as follows: (1) Furrow spines 5, the inner 
massive, blunt, subprismatic, with flattened side to actinostome. The next two are shorter and 
weaker, flattened or prismatic, with a rounded tip. The 2 outermost are shorter still and thicker, 
not constant as to shape, usually irregular. (2) Actinal surface is covered with granules. A series 
extends along margin of median suture. These are largest, are flat, subquadrate, or pentagonal, 
irregular, and diminish in size abruptly at inner end of plate, the, series terminating a short distance 
from the teeth. Another series follows margin adjacent to first adambulacral, and is continued inward 
parallel with furrow series, the latter portion containing a few compressed, upright, round-tipped 
granules, irregularly disposed. Several small granules are present between the inner ends of com- 
panion superficial series. 
Actinal interradial areas well developed, paved with large actinal intermediate plates arranged in 
series parallel to ambulacral furrow. Those adjacent to adambulacrals are largest and most regular, 
being subquadrate save for the outer margin, which is usually angular or rounded. They extend to 
the fifteenth inferomarginal, or three-fotirths length of raj?, while other intermediate plates do not 
extend beyond basal fourth of ray, being smaller and irregularly polygonal in shape. The outer por- 
tion of the series adjacent to adambulacrals is interrupted by the inferomarginals touching the latter, 
thus separating the intermediate plates. On the ray these pedicellarise are not present on every plate. 
Each is surrounded by heavy, quadrate, oblong, or roundish granules in a single series, with indications 
occasionally of an incomplete intermediate series of small granules between successive plates. There 
with an extensive, angular, 
